Resilient pipe cap



1955 E. J. MICKELSON RESILIENT PIPE CAP Filed April 28, 1953 INVENTOR.

ELMER J. MICKELSON ATTORNEY United States PatentO RESILIENT PIPE CAP Elmer J. Mickelson, Portland, Greg.

Application April 28, 1953, Serial No. 351,586

3 Claims. (Cl. 220-42) My present invention comprises a cap for a pipe, the device being of utility to close the upper ends of the filling tubes of buried fuel storage tanks. Such filling tubes are usually externally threaded and are usually closed by a metallic pipe cap havingi'nternal threads matching the threads of the filling tube. The tubes may project above the surface of the ground so as to locate the upper end thereof above the level of any standing water, but in many installations the upper ends of the tubes must be placed below ground level in a well, which may or may not be provided with a lid. In the latter case the well may become filled with water above the level of the lower edge of the cap, which quite often results in the entry of water into the tank by capillary action along the path provided by the matching grooves of the cap and pipe. This harmful result may be avoided by permitting the upper end of the tube to project above the ground, but this is subject to the danger that vehicles may damage the tube, and is undesirable since it presents a pedestrian hazard. In either type of installation the cap may rust onto the tube with the result that tools are required to remove it and a careless person may strip the threads of the cap or tube or both. With either type of installation a rust-weakened pipe may be broken loose from the tank when tools are used to unscrew the cap. The present invention provides a resilient cap which may he used with any filling tube, whether new and in good condition or old and damaged, and having any type of threads thereon.

The principal object of the present invention is to provide a cap which will prevent the entry of moisture into the tube even though the upper end of the tube should be below the surface of standing water.

A further object of the present invention is to provide a cap which will positively seal the upper end of a filling tube regardless of whether the threads of the tube are worn or damaged, and regardless of whether the tube may have been forced out of round to a limited extent.

A further object of the present invention is to provide an inexpensive cap which may be used to replace lost or damaged caps for buried filling tanks, regardless of the condition of the filling tube.

In the drawings,

Fig. l is a diametrical section through the cap of the present invention; and

Fig. 2 is a similar section through the cap of the present invention applied to a filling tube.

The present invention comprises a body of rubberous, resiliently deformable material of the type which is immune to the attack of oils and greases. The body is resilient and deformable under manual pressure to a limited extent throughout so that it may be forced onto the end of the tube as shown in Fig. 2, and so that it may adapt itself to tube ends which are of different thicknesses and diameters, or slightly out of round. The body comprises a cylindrical wall of substantial thickness, and substantially as long as the diameter of the body, and an integral top 11 of similar thickness. The

2,727,651 Patented Dec. 20, 1955 inner cylindrical surface of the wall 10 is provided with a plurality of annular grooves 12 of substantial width and depth in comparison to standard pipe threads, providing therebetween a plurality of spaced, parallel ridges 13. The cap comprises an internal plug consisting of a concentric flange 14 projecting longitudinally from the top 11 and having downwardly tapering, inner and outer walls 15 and 16, respectively, the base or upper portion of the flange being of substantial thickness, approximately equal to the thickness of the wall 10, and the edge 1 of the flange being narrow. The distance between the lower edge of the surface 16 is greater than the thickness of a steel pipe 17 of corresponding diameter, and the distance between the upper portion of the surface 16 and the adjacent ridge 13 is lesser than the thickness of the rim of a screw-threaded pipe 17 of corresponding diameter. Preferably the lower portion of the inner surface of the wall 10 is chamfered, as shown at 18, whereby the extreme lower edge inner diameter of the wall 10 is greater than the external diameter of the pipe 17 so as to facilitate placing of the cap. Also, the upper, outer corner of the cap is rounded, as indicated at 19, whereby to provide means for caps to be slightly nested when stood upright on a storage shelf.

When the cap is placed on the upper end of the tube, as shown in Fig. 2, the upper end of the tube is tightly wedged between the surface 16 and the adjacent ridges 13, thus compressing the material of the cap adjacent thereto and forcing the ridges and the plug firmly into contact with the inner and outer surfaces of the tube. The internal diameter of the ridges 13 is lesser than the external diameter of a pipe 17 of corresponding diameter so that the Wall 10 is stretched in order to admit the tube, thereby compressing the material of the wall 10 and forcing the ridges 12 into firm engagement with the threads. Since the threads are of lesser vertical dimensions than the ridges, each parallel ridge 12 crosses at least one of the threads. The material of a ridge closely approaches or engages the bottom of the adjacent pipe thread at one point, but stands far outwardly therefrom at other points, thus providing an air gap to break any capillary passage leading into the interior of the tube. Water is thereby prevented from entering the tank, and the compressed internal plug provided by the flange 14 prevents the escape of fumes from the tank.

Having illustrated and described a preferred embodiment of the present invention, it should be apparent to those skilled in the art that the same permits of modification in arrangement and detail. I claim as my invention all such modifications as come within the true spirit and scope of the appended claims.

I claim:

1. A pipe cap for use in association with a filler tube for an underground tank comprising a cup-shaped member composed entirely of resilient, rubberous material, said material being readily deformable to a limited extent under manual pressure, said member having a cylindrical wall of uniform internal diameter and a top, and an integral, internal plug depending from said top in concentric relation to and spaced inwardly from said wall, said internal plug comprising an annular flange having tapered inner and outer walls, said flange being relatively thick where it joins said top and thin at its lower edge, and the entire inner surface of said wall having a plurality of annular grooves therein providing a plurality of parallel ridges.

2. A pipe cap for use in association with a filler tube for an underground tank comprising a cup-shaped member composed entirely of resilient, rubberous material, said material being readily deformable to a limited extent under manual pressure, said member having a cylindrical wall of uniform internal diameter and a top, and

an integral, internal plug depending from said top in' concentric relation to and spaced inwardly from said wall, said internal plug comprising an annular flange having tapered inner and outer walls, said flange being relatively thick where it joins said top and thin at its lower edge, the entire inner surface of said wall having a plurality of annular grooves therein providing a plurality of parallel ridges, the spacing and depth of said grooves being greater than the spacing and depth of the screw threads for pipe of a corresponding diameter whereby every one of said ridges crosses at least one of the threads of a threaded pipe capped by the resili ent cap.

3. A pipe cap for use in association with a filled tube for an underground tank comprising a cup-shaped member composed entirely of resilient, rubberous material, said material being readily deformable to a limited extent under manual pressure, said member having a cylindrical wall of uniform internal diameter and a top, and an integral, internal plug depending from said top in concentric relation to and spaced from said wall, said internal plug comprising an annular flange having tapered inner and outer walls, said flange being relatively thick where it joins said top and thin at its lower edge, the inner surface of said wall having a plurality of annular grooves therein from top to bottom providing a plurality of parallel ridges, the radial distance between the uppernal plug being lesser than the wall thickness of a pipe of corresponding diameter whereby the material of said wall and said flange is placed under compression when 5 the cap is firmly seated on a pipe, the spacing and depth of said grooves being greater than the spacing and depth of the screw threads for pipe of a corresponding diameter whereby every one of said ridges crosses at least one of the threads of a threaded pipe capped by the resilient 10 cap.

References Cited in the file of this patent UNITED STATES PATENTS 5 Re. 18,669 Duffy et a1 Nov. 29, 1932 1,120,369 Booraem et al Dec. 8, 1914 1,556,966 Selig Oct. 13, 1925 1,595,323 Van Sant, Jr. Aug. 10, 1926 1,959,262 Colabrese May 15, 1934 20 2,321,667 Foster June 15, 1943 2,362,250 Durst Nov. 7, 1944 2,393,578 Waite Jan. 22, 1946 2,669,369 Towns Feb. 16, 1954 FOREIGN PATENTS 23 471,834 Great Britain Sept. 13, 1937 492,200 Great Britain Sept. 16, 1938 

